Oil passage structure for automatic transmission

This application claims priority to Japanese Patent Application No. 2024-050897, filed on Mar. 27, 2024, which is incorporated herein by reference in its entirety.

The technology disclosed herein belongs to a technical field related to an oil passage structure for an automatic transmission.

Conventionally, an oil passage structure having an oil passage formed using the housing of an automatic transmission has been known.

In Patent Literature 1, on a transaxle cover attached to an opening of a transaxle case in which a vehicle power transmission device including a motor generator is accommodated, an oil supply passage is provided to take oil supplied by an oil pump to the outside of the transaxle case.

In Patent Literature 1, the oil supply passage extends in a radial direction of a main shaft of the transaxle (automatic transmission). Moreover, the oil supply passage is formed integrally with the transaxle cover by casting using a core.

When an oil passage is formed by casting as in the oil passage structure described in Patent Literature 1, the oil passage has a tapered shape due to a draft angle of a core pin for casting. When the oil passage extends in the radial direction of the main shaft, the oil passage spreads in the axial direction of the main shaft, which leads to an increase in the size of the automatic transmission in the axial direction.

To limit an increase in the size of the automatic transmission in the axial direction, it is conceivable to construct the oil passage by machining the axially facing surfaces of members which constitute the automatic transmission. However, when constituent components of the automatic transmission are disposed near the facing surfaces, it is necessary to construct the oil passage having a required cross-sectional area of a channel while avoiding interference with the constituent components. When the constituent components are spaced apart from the oil passage to avoid interference between the oil passage and the constituent components, the automatic transmission ends up in larger size in the axial direction.

The technology disclosed herein has been developed in consideration of the above point, and an object of this technology is to provide an oil passage structure that can limit an increase in the size of an automatic transmission.

In order to solve the above problem, a first aspect of the technology disclosed herein is directed to an oil passage structure for an automatic transmission. The oil passage structure includes: a first member constituting a first wall extending in a radial direction of a main shaft of the automatic transmission; a second member constituting a second wall that extends in the radial direction, and is arranged to face the first wall from one side in an axial direction of the main shaft; and an oil passage constituted by a first groove formed on a surface of the first wall on the one side in the axial direction and extending in the radial direction, and a second groove formed on a surface of the second wall on the other side in the axial direction and extending in the radial direction, in which the first wall has a first recess on a surface on the other side in the axial direction, the first recess being recessed toward the one side in the axial direction, the second wall has a second recess on a surface on the one side in the axial direction, the second recess being recessed toward the other side in the axial direction, at least a portion of a first component is disposed in the first recess, at least a portion of a second component is disposed in the second recess, and in the oil passage, a second passage located at a position corresponding to the second recess in the radial direction, the second passage is located on the other side in the axial direction relative to a first passage located at a position corresponding to the first recess in the radial direction.

In the first aspect, the first component can be disposed closer to the second passage while being spaced apart from the first passage in the axial direction. On the other hand, the second component can be disposed closer to the first passage while being spaced apart from the second passage in the axial direction. This makes it possible to reduce the size in the axial direction while avoiding interference between the first component, the second component, and the oil passage. Therefore, it is possible to limit an increase in the size of the automatic transmission.

According to a second aspect, in the first aspect, the depth of the first groove is shallower in the first passage than in the second passage, and the depth of the second groove is shallower in the second passage than in the first passage.

In the second aspect, by making the first groove shallower in the first passage corresponding to the position of a first protruding portion, and by making the second groove shallower in the second passage corresponding to the position of a second protruding portion, it is possible to form the oil passage into a shape matching the first recess and the second recess while ensuring the cross-sectional area of a channel of the oil passage. Consequently, it is possible to limit an increase in the size of the automatic transmission.

According to a third aspect, in the first aspect, the first passage is constituted by only the second groove out of the first groove and the second groove, and the second passage is constituted by only the first groove out of the first groove and the second groove.

In the third aspect, the first recess and the second recess can be made as deep as possible. Consequently, the first component can be placed as close as possible to the one side in the axial direction, and the second component can be placed as close as possible to the other side in the axial direction. Therefore, it is possible to limit an increase in the size of the automatic transmission.

According to a fourth aspect, in the first to third aspects, the first member is a motor housing that accommodates a motor, the first component is a rotation angle sensor, the motor is located on the other side in the axial direction relative to the first component, and a coil is located near the first component.

In the fourth aspect, since the coil of the motor is located near the first component, the motor and the first component need to be spaced apart from each other in the axial direction or the radial direction. The first component can be spaced apart from the motor in the axial direction as far as possible by disposing the first component in the first recess. Therefore, it is possible to limit an increase in the size of the automatic transmission.

According to a fifth aspect, in the fourth aspect, a torque converter is disposed on the radial-direction inner side relative to the motor, the first recess is located on the radial-direction outer side relative to the second recess, and the first component measures the rotation angle of the torque converter and is located on the radial-direction outer side relative to the second component.

In the fifth aspect, since the torque converter is located on the radial-direction inner side of the motor, it is necessary to dispose the first component side by side with the torque converter in the axial direction. Since the first recess is located on the radial-direction outer side relative to the second recess, the first component can be disposed as far outward as possible in the radial direction. Consequently, it is possible to dispose the torque converter and the first component side by side in the axial direction in a state in which the torque converter and the first component are placed closer to each other in the axial direction. Therefore, it is possible to limit an increase in the size of the automatic transmission.

According to a sixth aspect, in any one of the first to third aspects, the second component is a bolt, and at least a portion of a bolt head of the second component is disposed in the second recess.

In the sixth aspect, the protruding amount of the bolt head from the second wall toward the one side in the axial direction can be limited as much as possible. Consequently, it is possible to limit an increase in the size of the automatic transmission.

According to a seventh aspect, in the sixth aspect, a third recess is located at the position of the bolt in the second recess, the third recess being recessed further toward the other side in the axial direction than the other portion of the second recess, and the bolt head is disposed in the third recess.

In the seventh aspect, the protruding amount of the bolt head from the second wall toward the one side in the axial direction can be limited as much as possible. Consequently, it is possible to limit an increase in the size of the automatic transmission.

According to an eighth aspect, in the seventh aspect, a transmission mechanism is provided at a position that is on the one side in the axial direction relative to the second wall and near the second recess.

In the eighth aspect, since the protruding amount of the bolt head is limited, the transmission mechanism can be placed as close as possible to the other side in the axial direction. Consequently, it is possible to limit an increase in the size of the automatic transmission.

As described above, according to the technology disclosed herein, it is possible to limit an increase in the size of the automatic transmission.

Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

shows an automatic transmissionhaving an oil passage structure according to Embodiment 1. The automatic transmissionis an automatic transmission that is mounted on a vehicle. The vehicle is a hybrid vehicle having an engine E and a motor. The automatic transmissionchanges the speed of rotation transmitted from the engine E or rotation of the motor, and outputs the rotation. Note that, in the description below, the term “axial direction” refers to a direction in which a main shaftof the automatic transmissionextends, the term “radial direction” refers to a direction orthogonal to the direction in which the main shaftextends, and the term “circumferential direction” refers to the circumferential direction of the main shaft. Furthermore, in the axial direction, the engine E-side is referred to as the axial-direction front side, and the opposite side to the engine E is referred to as the axial-direction rear side. The axial-direction front side and the axial-direction rear side mentioned here do not limit the actual layout of the automatic transmission.

The automatic transmissionincludes a damper, a torque converter, and a transmission mechanism.

The damperis disposed on the axial-direction rear side of the engine E. The damperis connected to an output shaft of the engine E. The damperreduces vibration caused by torque fluctuations of the engine.

The torque converteris disposed on the axial-direction rear side of the damper, and is accommodated in a motor housingin which the motoris accommodated. In the motor housing, the motoris configured such that a rotoris disposed on the radial-direction inner side of a stator, and the torque converteris located on the radial-direction inner side relative to the rotor. The motor housingis made of aluminum or an aluminum alloy. The motor housingis an example of a first member.

The torque converteris connected through a transmission partand a clutchconnected to the output shaft of the engine E. The transmission partis also connected to the rotorof the motor. When the clutchis released, the output shaft of the engine E and the transmission partare disconnected. On the other hand, when the clutchis engaged, the engine E and the transmission partare connected. The clutchis engaged when the rotation of the engine E is transmitted to the transmission part. On the other hand, the clutchis released, for example, when the vehicle is driven only by the rotation of the motorwithout using the engine E, or when regenerative charging is performed.

The torque convertertransmits power through a fluid. The torque converterhas a lock-up clutch. When the lock-up clutchis released, the rotations of the engine E and the motorare transmitted to the main shaftthrough the fluid. When the lock-up clutchis engaged, the rotations of the engine E and the motorare transmitted from the transmission partto the main shaftwithout the fluid.

The transmission mechanismchanges the speed of the output transmitted from the main shaft. The transmission mechanismis accommodated in a transmission casedisposed on the axial-direction rear side of the motor housing. The transmission caseis fixed to the motor housing. The transmission mechanismis configured to be able to form a plurality of gear stages having a different transmission gear ratio by a combination of a plurality of gears having different numbers of teeth. The gear stages are switched by hydraulic control.

A coverattached to the motor housingis disposed in the transmission case. The coveris attached to a first wallthat is provided on the axial-direction rear side of the motor housingand extends in the radial direction. The coverincludes a second wallthat extends in the radial direction and is arranged to face the first wallfrom the axial-direction rear side. The coveris made of iron. As will be described in detail later, the first walland the second wallform an oil passagethrough which oil flows. The coveris an example of a second member.

As shown in, a valve bodyfor supplying the oil to the clutch, the lock-up clutch, the transmission mechanism, etc. is fixed to a lower portion of the transmission case. The valve bodyis accommodated in an oil panin which the oil is stored. The oil is pumped up by an oil pump (not shown), and supplied to the respective locations through the valve body.

The automatic transmissionincludes the oil passagefor circulating the oil from the valve bodytoward the radial-direction inner side. The oil passageis constituted by a first grooveformed in the first wall, and a second grooveformed in the second wall. In order to describe the configuration of the oil passage, the first walland the second wallwill be described in detail below with reference to. Note that, in, the up-down direction is inverted from that in.

As shown in, the first wallincludes a first front surfacewhich is a surface on the axial-direction front side, and a first rear surfacewhich is a surface on the axial-direction rear side.

A resolveris attached to a portion on the radial-direction outer side of the first front surface. The resolveris a rotation angle sensor that measures the rotation angle of the torque converter. The resolverincludes a measuring partthat measures the rotation angle, a mounting partthat is attached to the first front surface, and a rotating rotorattached to the torque converter. The mounting partextends from the measuring parttoward the radial-direction outer side, and an end portion on the radial-direction outer side is attached to the first front surfacewith a bolt. The bolt is attached to the first wallat a portion where the bolt does not interfere with the oil passage. The measuring partprotrudes from either side of the mounting partin the axial direction. The position of an end portion of the measuring parton the axial-direction front side overlaps with the position of an end portion of the torque converteron the axial-direction rear side in the axial direction. The rotating rotoris located on the axial-direction rear side relative to the torque converter. The measuring partdetects the position of the rotating rotor, and whereby the resolvermeasures the rotation angle of the torque converter. The resolveris an example of a first component.

In the motor housing, the motoris located on the axial-direction front side relative to the resolver. The position of an end portion of the resolveron the radial-direction outer side overlaps with the position of the statorof the motorin the axial direction. A coilwound around the statoris located near the resolver.

As shown in, in the first front surface, a radial-direction outer side portion is located rearward in the axial direction relative to a radial-direction inner side portion. More specifically, the first front surfacehas a first recessthat is provided at a position in the radial direction at which the resolveris located, and that is recessed rearward in the axial direction. The position of a rear end surfaceof the first rear surfaceis the same in the portion where the first recessis provided and other portions.

A portion of the measuring partof the resolveris disposed in the first recess. By providing the first recess, the resolvercan be spaced apart from the coilof the motorin the axial direction.

The first grooveis formed in the first rear surface. The first grooveextends in the radial direction. The depth direction of the first groovecoincides with the axial direction.

The first grooveincludes a first outer groovelocated relatively outward in the radial direction, and a first inner groovelocated relatively inward in the radial direction. The position of the first outer groovecorresponds to the position in the radial direction at which the first recessis provided. The bottom of the first outer grooveis located on the axial-direction rear side relative to the bottom of the first inner groove. Therefore, the first outer grooveis shallower than the first inner groove. The difference between the depth of the first outer grooveand the depth of the first inner grooveis the same as the depth of the first recess.

As shown in, a plurality of (eight in this example) first groovesare provided. Each of the first grooveshas the same width. In each of the first grooves, the first outer grooveis shallower than the first inner groove

In the first rear surface, a plurality of first auxiliary groovesare provided in addition to the first grooves. The first auxiliary grooveis a portion in which an auxiliary space for preventing communication between adjacent oil passagesis formed. The first auxiliary grooveis disposed, for example, between an oil passage leading to the clutchand an oil passage leading to the transmission mechanism. The first auxiliary groovecommunicates with the inner space of the motor housingthrough a hole or groove. The oil that has entered the space formed by the first auxiliary grooveis discharged through the hole or groove.

The first wallhas a through-holepassing through the first wall. The through-holeis a hole through which the main shaftand a later-described cylindrical partof the coverpass.

As shown in, the second wallincludes a second front surfacewhich is a surface on the front side in the axial direction, and a second rear surfacewhich is a surface on the rear side in the axial direction.

The second wallis connected to the first wallwith a bolt. The axial direction of the boltcoincides with the axial direction of the main shaft. The boltis positioned so as not to overlap with the resolverin the radial direction, more specifically is positioned inward in the radial direction relative to the resolver. The boltis fastened to the first walland the second wallat a portion where the boltdoes not interfere with the oil passage. A bolt headof the boltis located on the axial-direction rear side of the second wall. The boltis an example of a second component.

As shown in, in the second rear surface, a radial-direction inner side portion is located forward in the axial direction relative to a radial-direction outer side portion. More specifically, the second rear surfacehas, at a position different from the first recessin the radial direction, a second recessrecessed forward in the axial direction. The second recessis located on the radial-direction inner side relative to the first recess. The position of the second recessoverlaps with the position of the torque converterin the radial direction. A portion of the bolt headis located in a portion of the second recesson the radial-direction inner side. The position of a front end surfaceof the second front surfaceis the same in the portion where the second recessis provided and other portions.